Imaging lens assembly

ABSTRACT

An imaging lens assembly is provided in the present disclosure. The imaging lens assembly includes a first lens with positive refractive power, a second lens with negative refractive power, a third lens with negative refractive power, a fourth lens with positive refractive power, and a fifth lens with negative refractive power. The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are arranged in sequence from the object side to the image side, and satisfy conditions provided in the present disclosure.

FIELD OF THE DISCLOSURE

The present disclosure relates to optical technologies, and moreparticular, to an imaging lens assembly applicable to a digital cameraof a mobile phone or a WEB camera, which uses CCD imaging components orCMOS imaging components with high resolution.

BACKGROUND

CCD imaging components and CMOS imaging components are used widely incamera device, to meet the requirements of miniaturization and goodperformance of the imaging components, a wide-angle lens assembly withgood optical characteristic, thin profile, and high luminous flux(namely, F number or Fno) is needed.

Japanese patent publication No. 2015-072424 discloses an imaging lensassembly including five lenses. However, as the shape of the second lensis inadequate, the optical parameters of the imaging lens assembly areas follow: Fno=2.25, 2ω≦74.6°, and TTL/IH≧1.517. In other words, theimaging lens assembly cannot meet the requirement of wide view angle,thin profile and high luminous flux.

Japanese patent publication No. 2015-060171 discloses another imaginglens assembly also including five lenses. However, as the shape of thefirst lens, the second lens and the third lens are inadequate ,theoptical parameters of the imaging lens assembly are as follow: Fno=2.25and 2ω≦75.6° 7. As can be seen, the imaging lens assembly also cannotmeet the requirement of wide view angle, thin profile and high luminousflux.

Accordingly, an improved imaging lens assembly which can overcome thedisadvantages described above is desired.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the embodiment can be better understood with referenceto the following drawings. The components in the drawing are notnecessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the present disclosure. Moreover,in the drawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 is a structural diagram of an imaging lens assembly related to anembodiment of the present disclosure;

FIG. 2 is a structural diagram of the imaging lens assembly inaccordance with the first embodiment of the present disclosure;

FIG. 3 is the longitudinal aberration of the imaging lens assembly ofFIG. 2;

FIG. 4 is the lateral color of the imaging lens assembly of FIG. 2;

FIG. 5 is the field curvature and distortion of the imaging lensassembly of FIG. 2;

FIG. 6 is a structural diagram of the imaging lens assembly inaccordance with the second embodiment of the present disclosure;

FIG. 7 is the longitudinal aberration of the imaging lens assembly ofFIG. 6;

FIG. 8 is the lateral color of the imaging lens assembly of FIG. 6;

FIG. 9 is the field curvature and distortion of the imaging lensassembly of FIG. 6.

DETAILED DESCRIPTION

The present invention will hereinafter be described in detail withreference to several embodiments.

Referring to FIG. 1, an imaging lens assembly LA according to anembodiment of the present disclosure is shown. The imaging lens assemblyLA includes a lens set with five lenses, that is, a first lens L1, asecond lens L2, a third lens L3, a fourth lens 4 and a fifth lens L5,which are arranged in order from the object side to the image plane. Aglass filter GF is arranged between the fifth lens L5 and the imageplane, the glass filter GF may be a cover glass or an IR filter.Alternatively, the glass filter GF may be arranged in other locations oreven removed from the imaging lens assembly LA.

The first lens L1 has a positive refractive power, the second lens L2has a negative refractive power, the third lens L3 also has a negativerefractive power, the fourth lens L4 has a positive refractive power,and the fifth lens L5 has a negative refractive power. In practice, thefive lenses L1 to L5 may be designed to have aspheric surfaces, so as tocompensate aberration in the imaging lens assembly LA.

The imaging lens assembly LA as provided in the present embodimentsatisfies the following conditions (1) to (3):

0.00≦|R1/R2|≦0.05   (1)

0.80≦|R3/R4|≦1.50   (2)

1.20≦|R5/R6|≦1.55   (³)

In the above conditions (1) to (3),

R1 is the curvature radius of the object side of the first lens L1;

R2 is the curvature radius of the image side of the first lens L1;

R3 is the curvature radius of the object side of the second lens L2;

R4 is the curvature radius of the image side of the second lens L2;

R5 is the curvature radius of the object side of the third lens L3; and

R6 is the curvature radius of the image side of the third lens L3.

The condition (1) defines the shape of the first lens L1. If theproportion value |R1/R2| is beyond the value range defined by condition(1), it is difficult to compensate the high order aberrations such asthe spherical aberration when the imaging lens assembly LA has a lessthickness and a wider view angle.

In addition, the proportion value |R1/R2| in condition (1) is preferredto be set in the value range as defined in the following condition(1-A):

0.00≦|R1/R2|0.035   (1-A)

The condition (2) defines the shape of the second lens L2. If theproportion value |R3/R4| is beyond the value range defined by condition(2), it is difficult to compensate the on-axis chromatic aberration whenthe imaging lens assembly LA has a less thickness and a wider viewangle.

In addition, the proportion value |R3/R4| in condition (2) is preferredto be set in the value range as defined in the following condition(2-A):

0.83≦|R3/R4|≦1.20   (2-A)

The condition (3) defines the shape of the third lens L3. If theproportion value |R5/R6| is beyond the value range defined by condition(3), it is difficult to compensate off-axis chromatic aberration whenthe imaging lens assembly LA has a less thickness and a wider viewangle.

In addition, the proportion value |R5/R6| in condition (3) is preferredto be set in the value range as defined in the following condition(3-A):

1.3≦|R5/R6|≦1.55   (3-A)

Moreover, the first lens L1 has a positive refractive power, andsatisfies the following condition (4):

0.60≦f1/f≦0.80   (4)

In the above condition (4),

f is the focal length of the image lens assembly LA; and

f1 is the focal length of the first lens 1.

The condition (4) defines the positive refractive power of the firstlens L1. If the proportion value f1/f is less than the minimum limit ofcondition (4), the positive refractive power of the first lens L1 may betoo strong to compensate aberration, and the imaging lens assembly L1 isdifficult to obtain a wide view angle. In contrast, when the proportionvalue f1/f exceeds the maximum limit of condition (4), the positiverefractive power of the first lens L1 is too weak, and is adverse to theminiaturization of the imaging lens assembly LA.

The third lens L3 has a negative refractive power, and satisfies thefollowing condition (5):

−30.00≦f3/f≦−10.00 (5)

In the above condition (5),

f is the focal length of the imaging lens assembly; and

f3 is the focal length of the third lens L3.

The condition (5) defines the negative refractive power of the thirdlens L3. If the proportion value f3/f is beyond the value range definedby condition (5), it is difficult to compensate the on-axis and off-axischromatic aberration when the imaging lens assembly LA has a lessthickness and a wider view angle.

Upon the condition that the five lenses L1 to L5 satisfy the aforesaidconditions, the imaging lens assembly LA is possible to have goodoptical characteristic as well as an ultra-thin profile and highluminous flux, and moreover, the imaging lens assembly LA may alsosatisfy the following parameter requirements: TTL/IH≦1.35, view angle2ω≧78°, and Fno≦2.2.

The following description describes the imaging lens assembly LAaccording to the present disclosure in detail with reference to severalembodiments; parameters of the imaging lens assembly LA are defined asfollows, in which the unit of each of distance, radius, and centralthickness is millimeter (mm):

f: the focal length of the imaging lens assembly LA;

f1: the focal length of the first lens L1;

f2: the focal length of the second lens L2;

f3: the focal length of the third lens L3;

f4: the focal length of the fourth lens L4;

f5: the focal length of the fifth lens L5;

Fno: F-number;

2ω: full view angle;

S1: the aperture stop;

R: a curvature radius of an optical surface, and may also be a centralcurvature radius of a lens;

R1: the curvature radius of the object side of the first lens L1;

R2: the curvature radius of the image side of the first lens L1;

R3: the curvature radius of the object side of the second lens L2;

R4: the curvature radius of the image side of the second lens L2;

R5: the curvature radius of the object side of the third lens L3;

R6: the curvature radius of the image side of the third lens L3;

R7: the curvature radius of the object side of the fourth lens L4;

R8: the curvature radius of the image side of the fourth lens L4;

R9: the curvature radius of the object side of the fifth lens L5;

R10: the curvature radius of the image side of the fifth lens L5;

R11: the curvature radius of the object side of the glass filter GF;

R12: the curvature radius of the image side of the glass filter GF;

d: an central thickness of the lens or an axial distance between lenses;

d0: the axial distance between the aperture stop S1 and the object sideof the first lens L1;

d1: the central thickness of the first lens L1;

d2: the axial distance between the image side of the first lens L1 andthe object side of the second lens L2;

d3: the central thickness of the second lens L2;

d4: an axial distance between the image side of the second lens L2 andthe object side of the third lens L3;

d5: the central thickness of the third lens L3;

d6: the axial distance between the image side of the third lens L3 andthe object side of the fourth lens L4;

d7: the central thickness of the fourth lens L4;

d8: the axial distance between the image side of the fourth lens L4 andthe object side of the fifth lens L5;

d9: the central thickness of the fifth lens L5;

d10: the axial distance between the image side of the fifth lens L5 andthe object side of the glass filter GF;

d11: the central thickness of the glass filter GF;

d12: the axial distance between the image side of the glass filter GFand the image plane;

nd: d line refraction index;

nd1: d line refraction index of the first lens L1;

nd2: d line refraction index of the second lens L2;

nd3: d line refraction index of the third lens L3;

nd4: d line refraction index of the fourth lens L4;

nd5: d line refraction index of the fifth lens L5;

nd6: d line refraction index of the glass filter GF;

ud: abbe number (i.e., dispersion coefficient)

u1: abbe number of the first lens L1;

u2: abbe number of the second lens L2;

u3: abbe number of the third lens L3;

u4: abbe number of the fourth lens L4;

u5: abbe number of the fifth lens L5;

u6: abbe number of the glass plate GF;

TTL: the total track length (i.e., an axial distance between the objectside of the first lens L1 and the image plane);

LB: the axial distance between the image side of the fifth lens L5 andthe image plane (including a thickness of the glass plate GF); and

IH: the image height.

y=(x ² /R)/[1+{1−(k+1)(x ² /R ²)}^(1/2) ]+A4x ⁴ +A6x ⁶ +A8x ⁸ +A10x ¹⁰+A12x ¹² +A14x ¹⁴ +A16x ¹⁶   (7)

In the above condition (7), R is then axial curvature radius, k is theconic coefficient, and A4, A6, A8, A10, A12, A14 and A16 are asphericalcoefficients.

Optionally, aspherical surfaces of the lenses L1-L6 may be obtainedaccording to condition (7); alternatively, the aspherical surfaces mayalso be obtained according to other conditions.

Embodiment 1

FIG. 2 illustrated an imaging lens assembly LA in accordance with thefirst embodiment of the present disclosure. TABLE 1 and TABLE 2 show thedetailed optical data of the imaging lens assembly LA.

The optical data in TABLE 1 includes the curvature radius R, the centralthickness d, the axial distance d between lenses, refraction index ndand abbe number ud of the lenses L1 to L5 in the imaging lens assemblyLA. The optical data in TABLE 2 includes conic coefficient(C-coefficient) k and aspherical coefficient of the lenses L1 to L5 inthe imaging lens assembly LA.

TABLE 1 R d nd νd S1 ∞ d0 = −0.200 R1 1.32067 d1 = 0.521 nd1 1.5441 ν156.12 R2 308.07362 d2 = 0.048 R3 −6.52179 d3 = 0.206 nd2 1.6397 ν2 23.53R4 7.76515 d4 = 0.320 R5 13.73259 d5 = 0.217 nd3 1.6397 ν3 23.53 R610.48313 d6 = 0.370 R7 −4.57750 d7 = 0.587 nd4 1.5441 ν4 56.12 R8−1.05491 d8 = 0.412 R9 −2.23086 d9 = 0.303 nd5 1.5352 ν5 56.12 R101.82793 d10 = 0.380 R11 ∞ d11 = 0.210 nd6 1.5168 ν6 64.17 R12 ∞ d12 =0.352

TABLE 2 C-coefficient aspherical coefficient k A4 A6 A8 A10 A12 A14 A16R1 0.0000E+00 −1.8652E−02 2.5012E−02 −1.2798E−01 −2.3686E−03 6.0308E−024.2520E−02 −3.9018E−01 R2 0.0000E+00 −4.4095E−02 −5.6359E−02 6.1137E−02−1.9783E−01 −1.7519E−01 3.0872E−02 1.9893E−01 R3 0.0000E+00 7.9246E−027.0145E−02 −4.2959E−02 −8.7575E−02 −9.1949E−02 1.8885E−02 3.3327E−01 R47.2308E+01 1.0577E−01 3.2528E−02 5.9471E−02 1.2003E−01 −2.3360E−01−2.4888E−01 4.4363E−01 R5 8.8934E+01 −2.6195E−01 2.3104E−02 −9.2197E−02−5.9638E−03 2.9836E−01 2.8662E−01 −5.5527E−01 R6 3.8228E+01 −1.9252E−01−5.4413E−02 2.4293E−02 5.9544E−02 5.5018E−02 4.8888E−02 −2.8697E−02 R71.1726E+01 1.4860E−02 −1.1352E−02 −3.7230E−02 4.6307E−03 3.1842E−031.6882E−03 2.8214E−03 R8 −9.7079E+00 −6.5434E−02 9.4545E−02 −4.2079E−026.7894E−09 −8.9432E−04 5.2881E−04 −1.9927E−04 R9 −3.9071E+00 −4.3364E−021.4049E−02 7.2638E−04 −3.2510E−04 −2.0486E−05 −6.4827E−06 2.1599E−06 R10−1.8604E+01 −6.2066E−02 1.8411E−02 −4.7743E−03 5.8141E−04 −4.0995E−05−6.8882E−07 8.3824E−07

The relevant optical data of the imaging lens assembly LA in the firstembodiment and the values defined in the aforesaid conditions (1) to (5)are shown in TABLE 5 as provided in the subsequent paragraphs.

As can be seen in TABLE 5, the imaging lens assembly LA in the firstembodiment satisfies the aforesaid conditions (1) to (5).

FIGS. 3-5 schematically illustrate the longitudinal aberration, thelateral color, the field curvature and distortion of the imaging lensassembly LA as provided in the first embodiment respectively. In FIG. 5,curve S represents the field curvature related to the sagittal plane,and curve T represents the field curvature related to the tangentialplane.

As can be seen, in the first embodiment, the view angle 2ω of theimaging lens assembly LA is 80.7°, the proportion value TTL/IH of theimaging lens assembly LA is 1.338, and the F number is 2.20. In otherwords, the imaging lens assembly LA as provided in the first embodimenthas an ultra-thin profile and a wide view angle with high luminous flux,and accordingly has good optical characteristics.

Embodiment 2

FIG. 6 illustrated an imaging lens assembly LA in accordance with thesecond embodiment of the present disclosure. TABLE 3 and TABLE 4 showthe detailed optical data of the imaging lens assembly LA.

The optical data in TABLE 3 includes the curvature radius R, the centralthickness d, the axial distance d between lenses, refraction index ndand abbe number ud of the lenses L1 to L5 in the imaging lens assemblyLA. The optical data in TABLE 4 includes conic coefficient(C-coefficient) k and aspherical coefficient of the lenses L1 to L5 inthe imaging lens assembly LA.

TABLE 3 R d nd νd S1 ∞ d0 = −0.200 R1 1.32399 d1 = 0.526 nd1 1.5441 ν156.12 R2 355.53042 d2 = 0.048 R3 −6.55181 d3 = 0.209 nd2 1.6397 ν2 23.53R4 7.80198 d4 = 0.312 R5 14.89340 d5 = 0.215 nd3 1.6397 ν3 23.53 R69.69845 d6 = 0.381 R7 −4.68363 d7 = 0.551 nd4 1.5441 ν4 56.12 R8−1.05516 d8 = 0.416 R9 −2.36387 d9 = 0.300 nd5 1.5352 ν5 56.12 R101.77356 d10 = 0.380 R11 ∞ d11 = 0.210 nd6 1.5168 ν6 64.17 R12 ∞ d12 =0.376

TABLE 4 C-coefficient aspherical coefficient k A4 A6 A8 A10 A12 A14 A16R1 0.0000E+00 −1.7911E−02 2.5431E−02 −1.2792E−01 −1.7725E−03 6.3301E−025.0670E−02 −3.7296E−01 R2 0.0000E+00 −4.4912E−02 −5.6503E−02 6.3064E−02−1.9455E−01 −1.7115E−01 3.6001E−02 2.0336E−01 R3 0.0000E+00 7.9233E−028.9081E−02 −4.5298E−02 −9.0888E−02 −9.4864E−02 1.4091E−02 3.3084E−01 R47.0744E+01 1.0782E−01 3.1113E−02 5.8667E−02 1.1929E−01 −2.3499E−01−2.5205E−01 4.3843E−01 R5 1.1771E+02 −2.8027E−01 2.5389E−02 −8.7283E−023.4021E−04 3.0528E−01 3.8505E−01 −5.4463E−01 R6 9.3813E+01 −1.9537E−01−5.4123E−02 2.4909E−02 5.9591E−02 5.4918E−02 4.7985E−02 −2.8041E−02 R71.2084E+01 1.4340E−02 −1.2626E−02 −3.8186E−02 4.0802E−03 2.9598E−031.6856E−03 2.7792E−03 R8 −3.6624E+00 −6.4987E−02 9.4751E−02 −4.2001E−026.8207E−03 −8.7852E−04 5.3131E−04 −2.0015E−04 R9 −3.9477E+00 −4.3255E−021.4072E−02 7.3052E−04 −3.2464E−04 −2.0455E−05 −6.4815E−06 2.1743E−06 R10−1.5889E+01 −6.1925E−02 1.8415E−02 −4.7780E−03 5.8024E−04 −4.1232E−05−7.1163E−07 6.3085E−07

The relevant optical data of the imaging lens assembly LA in the secondembodiment and the values defined in the aforesaid conditions (1) to (5)are shown in TABLE 5 as provided in the subsequent paragraphs. As can beseen in TABLE 5, the imaging lens assembly LA in the second embodimentsatisfies the aforesaid conditions (1) to (5).

FIGS. 7-9 schematically illustrate the longitudinal aberration, thelateral color, the field curvature and distortion of the imaging lensassembly LA in the second embodiment respectively. In FIG. 9, curve Srepresents the field curvature related to the sagittal plane, and curveT represents the field curvature related to the tangential plane.

As can be seen, in the second embodiment, the view angle 2ω of theimaging lens assembly LA is 80.4°, the proportion value TTL/IH of theimaging lens assembly LA is 1.337, and the F number is 2.20. In otherwords, the imaging lens assembly LA as provided in the second embodimenthas an ultra-thin profile and a wide view angle with high luminous flux,and accordingly has good optical characteristics.

TABLE 5 shows the values of the imaging lens assembly LA in relevant tothe conditions (1) to (5) according to both the first embodiment and thesecond embodiment. Moreover, in TABLE 5, the unit of the value 2ω isdegree(°), and the units of the values f, f1, f2, f3, f4, f5, f6, TTL,LB and IH are millimeter (mm).

TABLE 5 Embodiment 1 Embodiment 2 Formulae |R1/R2| 0.004 0.004 Formula(1) |R3/R4| 0.840 0.840 Formula (2) |R5/R6| 1.310 1.536 Formula (3) f1/f0.721 0.718 Formula (4) f3/f −21.056 −13.001 Formula (5) Fno 2.20 2.202ω 80.7 80.4 TTL/IH 1.338 1.337 f 3.377 3.398 f1 2.436 2.441 f2 −5.510−5.535 f3 −71.105 −44.176 f4 2.380 2.376 f5 −1.830 −1.847 TTL 3.9263.924 LB 0.942 0.966 IH 2.934 2.934

In summary, the imaging lens assembly LA as provided in the presentdisclosure has good optical characteristic, high luminous flux as wellas an ultra-thin profile, and moreover, the imaging lens assembly LAsatisfies the following parameter requirements: TTL/IH≦1.35, view angle2ω≧78°, and Fno≦2.2. Therefore, the imaging lens assembly LA isapplicable to a digital camera of a mobile phone or a WEB camera, whichuses CCD imaging components or CMOS imaging components with highresolution.

It is to be understood, however, that even though numerouscharacteristics and advantages of the present embodiment have been setforth in the foregoing description, together with details of thestructures and functions of the embodiment, the disclosure isillustrative only, and changes may be made in detail, especially inmatters of shape, size, and arrangement of parts within the principlesof the invention to the full extent indicated by the broad generalmeaning of the terms in which the appended claims are expressed.

What is claimed is:
 1. An imaging lens assembly, comprising: a firstlens with positive refractive power; a second lens with negativerefractive power; a third lens with negative refractive power; a fourthlens with positive refractive power; and a fifth lens with negativerefractive power; wherein the first lens, the second lens, the thirdlens, the fourth lens, and the fifth lens are arranged in sequence fromthe object side to the image side, and satisfy following conditions (1)to (3):0.00≦|R1/R2|≦0.05   (1)0.80≦|R3/R4|≦1.50   (2)1.20≦|R5/R6|≦1.55   (³) wherein R1 is the curvature radius of the objectside of the first lens, R2 is the curvature radius of the image side ofthe first lens; R3 is the curvature radius of the object side of thesecond lens, R4 is the curvature radius of the image side of the secondlens; R5 is the curvature radius of the object side of the third lens,and R6 is the curvature radius of the image side of the third lens. 2.The imaging lens assembly of claim 1, further satisfying the followingcondition (4):0.60≦f1/f≦0.80   (4) wherein f is the focal length of the imaging lensassembly, and fl is the focal length of the first lens.
 3. The imaginglens assembly of claim 1, further satisfying the following condition(5):−30.00≦f3/f≦−10.00 (5) wherein f is the focal length of the imaging lensassembly, and f3 is the focal length of the third lens.